The present invention relates to a corrugated strip made of sheet material, especially plastically deformed sheet metal, for a packing module for treating a fluid, of the type defining flow channels for the fluid and comprising a spanning region, the channels of which define, in side view, peak/trough lines having a general direction inclined to a general flow direction of said fluid, the strip furthermore including at least one transition region adjacent to the spanning region, the direction of the peak/trough lines of which transition region progressively approaches the general flow direction of said fluid.
The term “packing” is understood to mean a device intended for mixing a phase and/or for bringing several phases flowing cocurrently or countercurrently into contact with one another. A heat and/or mass exchange and/or a chemical reaction may in particular take place in the packing. One particular application of the invention lies in the columns for separating gas mixtures, especially air distillation columns.
Mentioned in the prior art are air distillation installations comprising cross-corrugated packing modules, which are also called packs. The modules comprise corrugated strips or metal sheets placed vertically in a parallel fashion, the corrugations of which sheets are oblique with respect to a general fluid flow direction in the installation, and are inclined alternately, generally crossed at 90°, from one sheet to another.
The packing modules are slipped into the distillation column so that the sheets of one module are angularly offset with respect to the sheets of an adjacent module about the axis of the column, generally by 90° from one module to another.
During use, the gas is constrained to change direction at such an angle in order to flow from one module to another, with a corresponding head loss at this location. Such a head loss causes accumulation of liquid in the lower region of the upper module and flooding of the column at this location, whereas the central portion of the modules has not yet reached its flooding point. This phenomenon reduces the treatment capacity of the column.
To reduce this effect, it has been proposed in the prior art to use packing modules having a structured interface region.
Such a packing module is disclosed, for example, in WO-A-97/16247.
In this module, the packing strips comprise, in their marginal regions, corrugations with curved peaks that extend, along the edge facing an adjacent module, parallel to the general flow direction of the fluids.
These curved corrugations join this edge of the strip to the corrugations lying in the spanning region of the module, which lie obliquely relative to the general flow direction of the fluids.
However, the packing strips disclosed in the aforementioned WO-A-97/16247 still generate a substantial head loss in the interface regions of the modules.